1. Field of the Invention
The present invention relates generally to riding mowers and, more particularly, to an improved suspension system for motive systems on such mowers or the like. Known art can be found in U.S. Class 280, subclass 124 and in other classes and subclasses.
2. Description of the Known Art
Those skilled in the art will appreciate that riding mowers have been a staple for maintaining residential yards, commercial lawns, golf courses and highway rights of way for many years. They are seen moving along grass in many settings including grassy center dividers and along the sides of roads in rough, sometimes rocky terrain, and in all sorts of attitudes from flat and level to severe side hills.
In many instances, an operator may be in the seat for hours, and even with a kidney belt, will suffer considerable discomfort and, in some cases, injury. Indeed, it is not inconceivable that the constant bouncing and jarring could cause an operator to lose control, resulting in damage to the operator and others.
The underlying purpose and function of the present invention is to provide an element of relief to an operator and increased vehicle control. The invention disclosed in U.S. Pat. No. 7,708,292 issued to Foster deals with these issues. While this invention works well for its intended purpose, an improved system that places a hydrostatic axle proximate a drive wheel improves vehicle stability while also promoting operator comfort.
Most of the other known riding mowers in use today have their wheels affixed directly to the frame of the mower. In the late '90s the self proclaimed leader in the field, David Ferris, and others filed an application for a suspension system for riding mowers. The application claims priority based on provisionals, at least one of which dates back to 1996, and was divided and one of those continuations-in-part issued as Ferris et al. U.S. Pat. No. 6,460,318. The patent features a four bar mechanism relatively common in automotive suspensions.
Known art which may be relevant to the present invention includes the following patents with their abstracts, the teachings of which are incorporated by reference.
Gordon U.S. Pat. No. 6,170,242 is yet another patent assigned to Ferris Industries and claims priority under a 1997 provisional, which is also claimed under the earlier mentioned Ferris et al. patent. Gordon, like Ferris et al., features a four bar mechanism.
A very early patent featuring a rubber bumper between two elements in an automotive structure is found in Hickman U.S. Pat. No. 3,737,174.
Several other patents offer variations on the same theme. See, for example, Dunlap et al. U.S. Pat. No. 3,669,467, which has additional buffering devices, such as springs, leaf or coil, and shock absorbing devices. Dunlap has a pair of cushions, but also uses a pair of rods 32 and 34, which attach directly to the frame rail.
Krakowiak et al. U.S. Pat. No. 5,979,920, uses the simple bumper between the frame rail and a leaf spring. This is a device which is common on many of the earlier motor vehicles.
Merkle U.S. Pat. No. 4,310,717, uses what he refers to as an elastomeric spring, again, between the frame rail and what he refers to as a web section which holds the axle upon which the wheel is connected. It appears in the drawing that there may be a shock absorber in the middle of this assembly.
Bonzer et al. U.S. Pat. No. 4,559,669, employs a resilient buffer 19 for a caster assembly. Heitzman U.S. Pat. No. 5,899,470 uses a couple of resilient buffers as part of a system for adjusting camber and caster. It is evident from these patents that using an elastomeric as a spring or shock absorber is not new in the art. All of these references seek, to a greater or lesser extent, some modulation of the amplitude and frequency of shock transmitted through a wheel of a vehicle, but are unsuited for a riding mower.
Also, commercially available equipment and components may be relevant, including hollow metal frames, shoe brushes and the like. Such equipment may be used in implementing an exemplary embodiment in accordance with the present invention.
None of these references, either singly or in combination, disclose or suggest the present invention. It is desirable to have a improved lawnmower to address the perceived shortcomings of the known art.
While it is evident from past attempts that suspension systems for lawnmowers are desirable, the known art is limited in its teaching and utilization, and an improved system is needed to overcome these limitations. An improved suspension system should provide a simple and efficient system for meeting the various needs of the users and the like.